Pregnancy Trimesters: Duration, Stages & What to Expect

The three stages of pregnancy are the first trimester, the second trimester, and the third trimester. Each trimester lasts for approximately three months.

First trimester: The first trimester begins on the first day of your last menstrual period and ends at week 12. During this stage, the embryo develops into a fetus, and the major organs begin to form. Common symptoms of the first trimester include fatigue, nausea, and breast tenderness.

Second trimester: The second trimester lasts from week 13 to week 27. During this stage, the fetus grows rapidly and begins to move and kick. The mother's belly begins to show, and she may start to feel Braxton Hicks contractions.

Third trimester: The third trimester lasts from week 28 to week 40. During this stage, the fetus continues to grow and mature. The mother's body prepares for childbirth, and she may experience more frequent Braxton Hicks contractions.

The length of pregnancy can vary from woman to woman. Some women give birth a few weeks before or after their due date, which is set at 40 weeks from the first day of the last menstrual period.